Hydraulic transmission

ABSTRACT

A hydraulic transmission for independently driving an agitator motor and a spin mechanism of an automatic washing machine with control mechanism for independently controlling the speed of each by using a manually adjustable rotary valve to establish the size of a variable-size orifice in the fluid exhaust line from the agitator motor and the spin mechanism to control the speed of same. The rotary valves are positioned in a stationary portion of the transmission to provide for connection to the manual adjustment means.

[451 lan. 13,1972

imite@ States Patent Wayman et al.

Simonds 2,918,795 12/1959 9|. 35 ww ww 7 w me, 79 54 l5 2,2, mm m n, eC mm N 1mm, B m mw. M me m wm A a R w T H m .m m M A R D Y H 41 U [72] Inventors: Rohm w.

[73] Assignee: Borg-Warner Corporation, Chicago, Ill,

[22] Filed:

Oct. 31, 1968 [2l] Appl. No.: 772,298

Primary Examiner- Edgar W. Geoghegan Attorney-Donald W. Banner, Lyle S. Motley, C. G. Stallings [52] U.S. Cl. ....60/53 1R, 68/23.7, 60/52 VM, and william S, McCun-y References Cited machine with control mechanism for independently controlling the speed of each by using a manually adjustable ro- UNITED STATES PATENTS tary valve to establish the size of a variable-size orice in the fluid exhaust line from the agitator motor and the spin mechanism to control the speed of same. The rotary valves are propositioned in a stationary portion of the transmission to vide for connection to the manual adjustment means.

7 Claims, 4 Drawing Figures 2,127,877 Maglott....

Johnson 3,409,270 l l/1968 Hulsey...... 1,677,499 7/1928 Smith....... 2,102,865 12/1927 CONTROL V.

HYDRAULIC TRANSMISSION SUMMARY OF THE INVENTION ln known washing machine structures such as described in U.S. Pat. No. 3,330,138, issued July ll, 1967, and copending application Ser. No. 671,675, filed Sept. 29, 1967, now U.S. Pat. No. 3,443,405 all of common assignee, speed control mechanisms are provided including means to establish a variable-size orifice. As is common in the. control of hydraulic motors, reciprocating valves are used to establish an orifice size to control the speed of the device.

The present invention incorporates rotary control valves in which a slot is provided between the center bore of a valve spool and an exhaust port so that by rotation of the valve an orifice size can be established. The rotary valves are advantageous in that a wide range of orifice sizes is provided and precise control can be obtained by means of the wide range of the orifice sizes available.

Further, in the construction of the present invention the components of the transmission mechanism are arranged in a stationary housing for a washing machine such that the rotary control valves are conveniently mounted in a section of the stationary case on opposite sides of the transmission. Thus the control of the valves is simplified as compared to known structures in that the valves are not in a rotating section of the transmission.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. l is a schematic view of a control system for a hydraulic transmission for a clothes washer embodying the principles of' the invention;

FIG. 2 is a view taken along the lines 2-2 of FIG. l;

FIG. 3 is a view taken along the lines 3-3 of FIG. 1; and

FIG. 4 is a cross-sectional view of the transmission in an actual washing machine installation.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, a washing machine is schematically illustrated comprising a tub adapted to hold a laundering fluid, a clothes container 11 and an oscillatable agitator 12. A hydraulic transmission 14 is schematically illustrated for independently driving the clothesbasket lll for effecting a centrifugal drying operation, herein referred to as the spin cycle, or the oscillatory agitator 12, herein referred to as the agitate cycle, of the automatic clothes washer. The transmission 14 includes a transmission inner housing generally designated as 15 within which most of the elements of the transmission are mounted. An electric motor 16 is provided having a water pump 17 driven thereby for recirculating water in the clothes container 11 of the automatic washer and a source of power 18 is illustrated for operating the motor 16. A cycle selector switch 19 is schematically illustrated in simplified form although in a washer installation this function would be per formed by a timer switch mechanism of known construction.

The important elements of the hydraulic transmission are as follows: a constant volume reversible fluid pump 21, an oscil latory agitator motor 22, a rotary control valve 23 for the agitator motor, a bypass/relief valve 24 for the agitator motor, rotary control valve 25 to selectively restrict the output of the pump 21 and a spin brake actuator 26.

A fluid sump 28 is provided which is schematically illustrated for convenience at various places in the illustration of' the invention, although in actual construction, one fluid sump 28 is provided into which all the exhaust connections for various elements of the transmission exhaust fluid pressure. Electric leads 29 and 30 interconnect the source of power 18 with the motor 16, the lead 30 being a ground line. Lead 31 connects the source of' power 18 to switch mechanism 19. Switch mechanism 19 is connected to the motor by a lead 32 or a lead 32a.

The hydraulic pump 2l includes a pumping element 35 and a rotatable pump-housing element 36 operative within a fixed case section 37.

Any of a number of well-known types of hydraulic pumps could adequately perform the functions of' the hydraulic pump 21, as for example, the crescent type or the gerotor type, but for reasons that will later be described, it is found that the vane-type pump will perform best in the present transmission. For this reason, the hydraulic pump 21 is illustrated as a vane pump.

The pumping element 35 consists of a rotor 38 connectable to a rotatable drive member 39 of the electric motor 16. The rotor 38 contains a series of radial slots 42. A plurality of vanes 43 is provided, each vane adapted to slide within a slot 42.

'Ihe rotatable pump housing element 36 consists of an annular disc mounted eccentric to the rotor 38 and is shown drivingly connected to the clothes container 1l. A pair of arcuate ports 44 and 45 is formed in the pump-housing element 36 for communicating fluid from the sump 28 to pump 2l and, after the fluid is pressurized, from the pump 2l. The ports 44 and 45 will either be inlet ports or exhaust ports depending upon the direction of rotation of the electric motor 16 and thereby the direction of rotation of the rotor 38.

A fluid conduit 47 is provided to communicate fluid from the sump 28 to port 45 when the motor 16 is operated in a direction so as to activate the spin circuit. A check valve 48 allows fluid flow only in a direction from the sump 28 into pump 21. Fluid conduit 49 is provided to communicate fluid from sump 28 to port 44 when the electric motor I6 is operated in a direction to activate the agitate circuit. Check valve 50 allows fluid flow only in a direction from the sump 28 into pump 21. Check valve 48 and 50 are spring biased open, the purpose of which will later be described.

The oscillatory agitator motor 22 includes a vane 52 mounted in a chamber 53 and has associated therewith a reversing valve 54. The vane 52 drives a shaft 51 which in tum is drivingly connected to agitator 12. Provided in the vane 52 is a slot 56 which at times communicates with a pair of ports 58, 59 and 60, 61 provided in the housing 15 adjacent the vane 52. Chamber 53 is connected to reversing valve 54 by conduits 64 and 65. Reversing valve 54 is also connected to the ports 60 and 61 by conduits 68 and 69, respectively.

The spin rotary control valve 25 and the agitator rotary control valve 23 each includes rotary valve spools 70 mounted in a bore 7l in a case section 72. Each of the rotary control valves 23 and 25 further includes a lever 73 actuatable to rotate the valve spool 70. Provided within the spool 70 of the valves 23 and 25 is a central bore 75 which is intersected by generally rectangular slots 76 provided in the valve spool 70. The control valves further each includes an inlet port 78 communicating with the bores 75 and an outlet port 79 communicating with the slots 76 and the sump 28. Control valve 25 further includes an elongated bore section 80 connected to the bore 75 which has a relief piston 81 slidably mounted therein. A spring 82 is provided in the bore section 80 urging piston 8l to the right against a stop pin 84. Rotary valve spool 70 for valve 25 has an additional port 86 therein communicating with an exhaust port 87 provided in the case section 72.

The bypass/relief valve 24 includes a piston 90 slidable within a bore 92 in the housing 15. A valve member 91 is provided which is fixed in position in bore 92. The piston has a counterbored section 94 receiving a spring 9S which also engages the valve member 91. Valve member 91 has a central bore 97 therethrough and has a valve seat 98 formed therein engaged by a ball 99. A spring 101 urges ball 99 against seat 98 and engages a disc 102 having a central bore 103 which is mounted in the end of the bore 92. Bore 92 has a port 105 connected to the sump 28 and further has a port 106 communicating with a chamber 107 at the left end of the valve as viewed in FIG. 1. Also provided is a port 108 and a port 109 connected to a chamber 1110 between piston 90 and valve member 91 and a restriction l1 1 is provided in the port 109. A conduit interconnects ports 106 and 109 which will later be described.

The improved brake actuator 26 includes a piston 120 which carries a collar 121. The collar 121 has an end 122 of a brake band 123 secured therein. The piston 120 is slidable in a bore 125 provided in the housing 15. The piston 120 is counterbored at 127 to receive spring 128 which engages the end of bore 125 and urges the piston 120 to the right as viewed in FIG. 1. Pressure ports 130 and 131 are provided for the brake actuator 26.

A fluid conduit 140 interconnects the port 44 of pump 2l, port 78 of valve 25, port 130 of brake actuator 26, and port 108 of bypass/relief valve 24. A fluid conduit 141 interconnects port 45 of pump 2l, ports 58 and 59 of agitator motor 22, port 131 of brake actuator 26, and ports 106 and 109 of the bypass/relief valve. A branch conduit 142 is provided connecting conduit 141 to the reversing valve 54. A conduit 144 connects port 78 of the agitator control valve 23 to each end of the reversing valve 54.

The operation of the improved transmission is as follows: when the wash cycle is selected by selector switch 19, pumping element 35 of pump 21 will be rotated in a counterclockwise direction by electric motor 16. The pump will draw fluid through port 44 from the sump 28 and through the open check valve 50. Pressure thus will be supplied by the pump 21 from port 45 into conduits 141 and 47. Until the pump builds up a certain pressure the spring in check valve 48 will keep the check valve open so that the pump does not have to start rotation against a load. After pressure in conduit 47 closes check valve 48 pressure in conduit 141 will be communicated to ports S8 and S9 of agitator motor 22 and will also be supplied to the center of reversing valve 54 by conduit 142. Depending upon the position of the reversing valve 54, pressure will be supplied from conduit 142 to either conduit 64 or 65 to pressurize chamber 53 on one side of the vane S2. Fluid on the other Side of the vane in chamber 53 is drained by means of the other conduit 64, 65 through reversing valve 54, conduit 144, and valve 23 to sump 28. When the vane reaches the end of its stroke, the slot 56 will interconnect, for example, pressure port 59 with port 61 to communicate pressure through conduit 69 to reversing valve 54 to change its position and pressurize the other side of the vane 52, in a manner more completely described in U.S. Pat. No. 3,373,660, issued Mar. 19, 1968, ofcommon assignee.

The pressure in conduit 141 will also be communicated through ports 106, 109 to chambers 107, 110 of bypass/relief valve 24. In the event the pressure in conduit 141 exceeds some predetermined maximum, ball 99 will move from seat 98 to relieve the pressure. In case of a rapid pressure surge, since the restriction 111 impedes flow into the chamber 110, the pressure in chamber 107 will momentarily exceed the pressure in chamber 1 10. Piston 90 will then move to the right to allow the surge pressure in conduit 141 to flow into port 108 and conduit 140 to return to the inlet port 44 of the pump.

During the agitate cycle of the machine the brake actuator 26 receives fluid pressure through port 131 to move the brake actuator piston 120 to the right to hold the brake band 123 expanded to engage the fixed case section 37 and thus hold the clothes basket 11 stationary. The spring 128 at the completion of the spin cycle, as will be described, moves the piston 120 to the right to expand the brake band 123 and stop the spinning of the basket as is more completely described in copending application Ser. No. 671,675, filed Sept. 29, 1967, mentioned above. However, the improved structure ofthe present invention utilizes the additional pressure through port 131 on piston 120 to engage the brake band with increased force to hold the clothes basket 11 stationary and thus eliminate the need for a pressure actuated positive stop pin mechanism to hold the clothes basket, as is previously known.

As described above, pressure is exhausted from reversing valve 54 into conduit 144 and port 78 into the bore 75 of rotary control valve 23. The spool 70 of valve 23 may be rotated such that an orifice of desired size is provided between the slot 76 and exhaust port 79. This orifice will control the flow of escape fluid from the unpressurized portion of chamber 53 of the agitator motor 22. Thus the speed of the agitator motor 22 can be conveniently controlled merely by adjusting the size of the orifice defined by the slot 76 and exhaust port 79 and thereby provide an infinitely variable control of the speed of agitator motor 22.

Once selector switch 19 is moved to select the spin cycle, electric motor 16 will rotate pumping element 35 of pump 21 clockwise thus drawing fluid from sump 28 through check valve 48 of conduit 47 into port 45. Pressure will be supplied then from port 44 to conduit 140 and conduit 49. As in the agitate cycle, check valve 50 will initially be open and will be closed by pressure in conduit 49 to allow the pump to begin rotation without being under load. The pressure in conduit will be supplied through port 130 to act on piston 120 of brake actuator 26 to move the piston to the left against the force of spring 128 to release engagement of brake band 123 with fixed case section 37 thus releasing the clothes basket 11 for rotation.

Pressure in conduit 140 will also be supplied through port 78 to bore 75 of rotary control valve 25. In a manner similar to operation of control valve 23, spool 70 of valve 25 may be rotated to define an orifice between slot 76 and port 79 of the valve 25. Thus the output of fluid pressure from pump 21 into conduit 140 may be variably restricted. As is more fully described in previously mentioned copending application Ser. No. 671,675, since the outer element of the pump 21 is connected to basket 11, restriction of the output fluid pressure to the sump through port 79 will tend to lock up the pump 21 and cause a reaction such that the basket 11 will be rotated. The speed of rotation of the basket 11 may thus be infinitely varied by adjustment of the size of the orifice defined by slot 76 and port 79 of valve 25. lf the pressure in conduit 140 exceeds some predetermined maximum, relief piston 81 will be moved against the force of spring 82 to open conduit 140 to the sump through port 87 of valve 25 to relieve excessive pressures.

As will be apparent, the rotary control valves 23 and 25 simplify previously used reciprocating valves to define an orifice size. The rotary valves 23, 25 are easily machined and provide precise control of orifice size. Further, the rotary valves can be conveniently mounted in a stationary part of the transmission to simplify the orifice control structure over that which is required when valves are installed in a rotary part in the transmission.

Referring to FIG. 4, the structural relationships of the components of the improved transmission are shown in an assembly for installation in a washing machine. A stationary case 200 including the case section 37 previously mentioned above is provided which has journaled in it at one end a drive shaft member 39 of electric motor 16 and has journaled in the other end an agitator drive shaft 51 and a hollow shaft 201 connected to drive clothesbasket 11. A general numeral 15 has previously been given for the housing structure which comprises in general the rotating part of the transmission mechanism. This rotating housing 1S is connected to the hollow shaft 201 and thus to the basket 1l.

Case 200 includes a case section 72 having a pilot portion 206 thereon in which drive member 39 is rotatably journaled. The control valves 23 and 25 are mounted in case section 72 of stationary case 200 on opposite sides of drive member 39 so that they may be conveniently controlled. Pilot portion 206 has rotary fluid communication with the rotating housing 15 to support the housing and to provide the necessary communication between the outlet ports of the pump 21 and the control valves 23 and 25.

As shown in FIG. 4 proceeding from left to right the housing 15 includes a section including brake actuator 26 and bypass/relief valve 24, a section containing pump 21 and a section containing agitator motor 22.

The case 200 also has an end section 208 in which shafts 51 and 201 are journaled. Case sections 37, 72 and 208 together define'a fluidtight reservoir 28 and container for the transmission. Casing 200 further includes a motor section 209 containing electric motor 16 and water pump 17.

As will be apparent from the illustrations of FIG. 4, the improved components of the present invention provide an extremely compact transmission mechanism in that the electric motor 16, water pump 17, pump 2l and agitator motor 22 are all mounted within a common housing and are coaxial. Rotary connections have been provided between the housing l5 and the stationary housing 200 so that the rotary control valves can be mounted in a stationary location and yet control operation of the parts contained in the housing l5. Further, the stationary case 200 not only provides a housing for the hydraulic transmission and its sump but also further provides a mounting for the electric motor and water pump which is isolated from the transmission and sump.

Various features of the invention have been particularly shown and described; however, it should be obvious to one skilled in the art that modifications may be made therein without departing from the scope of the invention.

We claim:

ll. A hydraulic transmission including: a sump for hydraulic fluid, a hydraulic pump connected to said sump including a pumping element and a pump-housing element, one of said elements being connected to an output member for selective rotation thereof, at least one variable-speed hydraulic motor in iluid communication with said hydraulic pump and said sump, a rst rotary valve means between said motor and said sump and defining a first selectively variable size orifice, control means associated with said valve means to vary the size of said orifice, so that by selectively varying the size of said oritice the fluid flow from said motor will be varied thereby selectively varying the speed of said variable-speed hydraulic motor a second rotary valve means including restricting means adapted to selectively restrict the flow of fluid from said pump whereby the rotation of said output member is controlled, said first rotary valve means including a valve spool having a central bore connected to said hydraulic motor, an exhaust port for said valve, said valve spool including a slot, said slot cooperating with said exhaust port to dene said variable-size orifice, said valve spool being rotatable to establish said variable-size orifice between said central bore and said exhaust port.

2. A hydraulic drive arrangement including a stationary case, said case including a first section containing a transmission mechanism, said case including a second section containing a drive motor, means connecting the transmission mechanism with said drive motor, said transmission connected to selectively drive a pair of output members joumaled in said case and extending from said first section, a pair of control valves for said transmission mechanism mounted in said stationary case, each of said control valves adapted to control the drive to one of said output members to control the speed of said output members.

3. A drive arrangement as claimed in claim 2 wherein said control valves comprise rotary control valves having means to rotate same to control said output members.

d. A drive arrangement as claimed in claim 3 wherein said drive motor, transmission and output members are coaxial.

5. A drive arrangement as claimed in claim 2 wherein said transmission mechanism includes a variable-speed hydraulic motor connected to one of said output members and a hydraulic pump including a pair of relatively rotatable pump elements, one of said pump elements being connected to one of said selectively driven output members.

6. A hydraulic drive arrangement including: a stationary case, a drive motor disposed within said case, hydraulic transmission means disposed within sad case and drivingly connected to said drive motor, a pair of selectively operable output members joumaled in and extending from said case, each of said output members operably associated with and driven by said hydraulic transmission means, a pair of control valves mounted in said stationary case each of said control valves associated with one of said output members and each of said control valves adapted to vary the speed of its corresponding output member and, said transmission, drive motor and output members being coaxial.

hydraulic drive arrangement including: a stationary case, an electric drive motor disposed within said case, hydraulic transmission means disposed within said case iricluding: a positive displacement hydraulic pump connected to said drive motor including a pair of pump elements, said pump having an inlet and an outlet, an oscillatory hydraulic motor in fluid communication with said positive displacement pump, an oscillatory output member joumaled in and extending from said stationary case, said oscillatory output member connected to and driven by said oscillatory hydraulic motor, a rotary output member joumaled in and extending from said stationary case, said rotary output member connected to and driven by one of said pump elements, a rst control valve mounted in said stationary case and in fluid communication with said hydraulic motor, said control valve adapted to vary the speed of said hydraulic motor and said oscillatory output member, a second control valve mounted in said stationary case and in fluid communication with said outlet of said hydraulic pump, said control valve adapted to vary the speed of said rotary output member.

k l# #I Ik 52 

1. A hydraulic transmission including: a sump for hydraulic fluid, a hydraulic pump connected to said sump including a pumping element and a pump-housing element, one of said elements being connected to an output member for selective rotation thereof, at least one variable-speed hydraulic motor in fluid communication with said hydraulic pump and said sump, a first rotary valve means between said motor and said sump and defining a first selectively variable size orifice, control means associated with said valve means to vary the size of said orifice, so that by selectively varying the size of said orifice the fluid flow from said motor will be varied thereby selectively varying the speed of said variable-speed hydraulic motor a second rotary valve means including restricting means adapted to selectively reStrict the flow of fluid from said pump whereby the rotation of said output member is controlled, said first rotary valve means including a valve spool having a central bore connected to said hydraulic motor, an exhaust port for said valve, said valve spool including a slot, said slot cooperating with said exhaust port to define said variable-size orifice, said valve spool being rotatable to establish said variable-size orifice between said central bore and said exhaust port.
 2. A hydraulic drive arrangement including a stationary case, said case including a first section containing a transmission mechanism, said case including a second section containing a drive motor, means connecting the transmission mechanism with said drive motor, said transmission connected to selectively drive a pair of output members journaled in said case and extending from said first section, a pair of control valves for said transmission mechanism mounted in said stationary case, each of said control valves adapted to control the drive to one of said output members to control the speed of said output members.
 3. A drive arrangement as claimed in claim 2 wherein said control valves comprise rotary control valves having means to rotate same to control said output members.
 4. A drive arrangement as claimed in claim 3 wherein said drive motor, transmission and output members are coaxial.
 5. A drive arrangement as claimed in claim 2 wherein said transmission mechanism includes a variable-speed hydraulic motor connected to one of said output members and a hydraulic pump including a pair of relatively rotatable pump elements, one of said pump elements being connected to one of said selectively driven output members.
 6. A hydraulic drive arrangement including: a stationary case, a drive motor disposed within said case, hydraulic transmission means disposed within said case and drivingly connected to said drive motor, a pair of selectively operable output members journaled in and extending from said case, each of said output members operably associated with and driven by said hydraulic transmission means, a pair of control valves mounted in said stationary case each of said control valves associated with one of said output members and each of said control valves adapted to vary the speed of its corresponding output member and, said transmission, drive motor and output members being coaxial.
 7. A hydraulic drive arrangement including: a stationary case, an electric drive motor disposed within said case, hydraulic transmission means disposed within said case including: a positive displacement hydraulic pump connected to said drive motor including a pair of pump elements, said pump having an inlet and an outlet, an oscillatory hydraulic motor in fluid communication with said positive displacement pump, an oscillatory output member journaled in and extending from said stationary case, said oscillatory output member connected to and driven by said oscillatory hydraulic motor, a rotary output member journaled in and extending from said stationary case, said rotary output member connected to and driven by one of said pump elements, a first control valve mounted in said stationary case and in fluid communication with said hydraulic motor, said control valve adapted to vary the speed of said hydraulic motor and said oscillatory output member, a second control valve mounted in said stationary case and in fluid communication with said outlet of said hydraulic pump, said control valve adapted to vary the speed of said rotary output member. 